1. Field of the Invention
The present invention relates to a control method and apparatus for controlling an engine, and in particular, controlling the combustion state of each of the cylinders in a desirable manner.
2. Description of the Prior Art
Japanese Patent Application Laid-Open No. 59-122763 (1984) discloses a method and apparatus of this generic type, for controlling combustion state in each cylinder of an engine. Therein, the rotating angular speed at an explosion cycle is detected in each of cylinders, and the combustion state is controlled based on the difference of the angular speed in each of cylinders.
In such a conventional technology, the combustion state is determined by comparing, for example, the angular speed of each of the cylinders. Therefore, this technology has the disadvantage that the-combustion state cannot be judged correctly because the combustion state of the other cylinder becomes a a source of error in the comparison. Moreover, it is not taken into consideration that the engine is brought to a better state after the deviation in combustion state in each of the cylinders is corrected.
Further, as disclosed in Japanese Patent Application Laid-Open No. 58-217732 (1983), control parameters for ignition and/or fuel injection are corrected to improve combustion when the variation in rotating angular speed is large.
Moreover, each of the foregoing control methods and controllers requires that the accuracy of a sensor detecting rotational speed be sufficiently higher than the accuracy required for the control, and no corrective measures are provided when the accuracy in rotating information detection deviates depending on the individual differences of the sensors.